The colon cancer (CRC) staging, at the time of disease diagnosis, is critical for patient survival, which ranges from 90% for patients with localized disease to meagre 13% for the ones with metastasis. Thus, improved understanding of the molecular regulation of CRC-progression and metastasis is critical and urgent, to develop novel therapies. In this regard, studies from our, and other laboratories, have provided strong support for a casual role for upregulated claudin- 1 expression in promoting CRC malignancy, especially metastasis. An upregulated (and mislocalized) claudin-1 expression in CRC patient samples associated predominantly with CRC metastasis to liver (58%) and lymph nodes (35%). Moreover, genetic manipulation of claudin-1 expression was sufficient to modulate metastatic ability of CRC cells lines in vitro and in vivo. Further analysis suggested essential roles of proto-oncogenes Src and EphA2 in claudin-1 mediated CRC progression. The key objectives of this proposal are to determine the roles of Src- and EphA2-signaling in fostering CRC malignancy under conditions of the dysregulated claudin- 1 expression, and preclinical testing of a novel claudin-1 inhibitor for its therapeutic efficacy in inhibiting CRC malignancy. To test our hypothesis we propose following studies: Specific Aim- 1. To determine how dysregulated claudin-1 expression promotes dissemination of colon cancer cell and metastasis; and Specific Aim-2. To test therapeutic efficacy of a novel anti-claudin-1 small molecule inhibitor (I-6) in inhibiting CRC malignancy. The outcome of this study are expected to have substantial impact on prevention/inhibition of CRC metastasis.